Absorption– The process by which a liquid is drawn
into and tends to fill permeable pores in a porous solid body;
also, the increase in mass of a porous solid body resulting
from the penetration of a liquid into its permeable pores.

Accelerating
Admixture – An admixture that will shorten the set
time of concrete.

Admixture
– A material other than water, cement, and aggregate,
used to modify concrete’s freshly mixed, setting, or hardened
properties.

Aggregate
– A granular material such as crushed stone, sand, gravel,
or iron blast-furnace slag, used with a cementing medium to
form hydraulic-cement concrete or mortar.

Air-Cooled
Blast-Furnace Slag – The material resulting from
solidification of molten blast-furnace slag under atmospheric
conditions; subsequent cooling may be accelerated by application
of water to the solidified surface.

Air
Content – The volume of air voids in cement paste,
mortar, or concrete, exclusive of pore space in aggregate particles,
usually expressed as a percentage of total volume of the paste,
mortar, or concrete.

Air
Entraining Admixture – An admixture that through
agitation in production of fresh concrete causes the development
of a system of microscopic air bubbles that increase its workability
and aid in freeze/thaw resistance.

Batch
– Production of a quantity of concrete based on volume,
i.e….a cubic yard.

Batch
Weights – The measured amount of sand, stone, cement,
and water that make up a batch or “load” of concrete.

Blast-Furnace
Slag – The nonmetallic product, consisting essentially
of silicates and aluminosilicates of calcium and other bases,
that is developed in a molten condition simultaneously with
iron in a blast furnace.

Caisson
– Usually cylindrical in shape. Part of a footing or foundation.

Calcium
Chloride – A 32% solution or a solid, when added to concrete
acts as a set accelerator.

Cement
– Known as Portland Cement, is a hydraulic product, which
means it sets and hardens when it chemically interacts with
water and is able to do this under water.

Cementitious
Material – An inorganic material or a mixture of
inorganic materials that sets and develops strength by chemical
reaction with water by formation of hydrates and is capable
of doing so under water.

Concrete
– A composite material that consists essentially of a
binding medium within which are embedded particles or fragments
of aggregate; in hydraulic-cement concrete, the binder is formed
from a mixture of hydraulic cement and water.

Curing
– Action taken to maintain moisture and temperature conditions
in a freshly-placed cementitious mixture to allow hydraulic
cement hydration and (if applicable) pozzolanic reations to
occur so that the potential properties of the mixture may develop.

Curing
Compound – A liquid that, when applied as a coating
to the surface of newly-placed concrete, forms a membrane that
retards the evaporation of water and, in the case of white pigmented
compounds, reflects heat.

D-Cracking
– In concrete, a series of cracks near to and roughly
parallel to features such as joints, edges, and structural cracks.

Fly
Ash – The finely divided residue that results from
the combustion of ground or powdered coal and that is transported
by flue gases from the combustion zone to the particle removal
system.

Granulated
Blast-Furnace Slag – The glassy, granular material
formed when molten blast-furnace slag is rapidly chilled, as
by immersion in water.

Grout
– A cementitious mixture, with or without admixtures,
that is used primarily to fill voids.

High
Range Water Reducer (Superplasticizer) – An admixture
that can produce a high slump concrete or produce considerable
reduction of water with a minimal effect to set time.

Laitance
– A layer of weak material derived from Cementitious material
and aggregate fines either: 1) carried by bleeding to the surface
or to internal cavities of freshly placed concrete, or 2) separated
from the concrete and deposited on the concrete surface or in
internal cavities during placement of concrete under water.

Lightweight
Aggregate – A low density aggregate such as expanded
clay or shale, used in lightweight concrete.

Pozzolan
– A siliceous or siliceous and aluminous material, which
in itself possesses little or no Cementitious value but will,
in finely divided form and in the presence of moisture, chemically
react with calcium hydroxide at ordinary temperatures to form
compounds possessing Cementitious properties.

Retarding
Admixture – An admixture that will lengthen the set
time of concrete.

Segregation
– The unintentional separation of the constituents of
concrete or particles of an aggregate, causing a lack of uniformity
in their distribution.

Setting
– The process, due to chemical reactions, occurring after
the addition of mixing water, that results in a gradual development
of rigidity of a cementitious mixture.

Slump
– Used to measure the consistency of ready mix concrete.
To perform the slump test, you fill an inverted funnel-shaped
cone with concrete. When the cone is removed, the concrete “slumps”.
The distance is measured to determine the slump.

Specific
Gravity – The ratio of mass of a volume of a material
at a stated temperature to the mass of the same volume of distilled
water at a stated temperature.

Vapor
Barrier – A membrane such as 4 mil plastic placed
on grade that when fresh concrete is placed on top of, minimizes
the transmission of water vapor into and through the hardened
concrete from the sub-grade.

Water
Reducing Admixture – An admixture that allows a decrease
in water without changing the slump of fresh concrete, or, allows
an increase in slump without an increase in water.

Water
/ Cement Ratio – The Ratio of the mass of water,
exclusive only of that absorbed by the aggregates, to the mass
of portland cement in concrete, mortar, or grout, stated as
a decimal.

Workability
of Concrete – That property determining the effort
required to manipulate a freshly mixed quantity of concrete
with minimum loss of homogeneity.

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2007. Decorative Concrete Institute, Inc. All Righs Reserved.
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